1. The MERMeX ( Marine Ecosystems Response in the Mediterranean Experiment ) action: Mediterranean Marine Ecosystem response to global and anthropogenic changes, retroactions 3 coordinators: Cécile Guieu, Richard Sempéré, Xavier Durieu De Madron A group of about one hundred scientists from ten laboratories LOV, Villefranche/Mer LMGEM, Marseille CEFREM, Perpignan

2. MOTIVATIONS Almost enclosed Sea but highly dynamic: residence time very short  quick answer of the system to natural and anthropogenic changes Strong links between 3 main domains: OCEAN/ ATMOSPHERE/CONTINENT  Proximity and importance of inputs and exchanges MERMeX Heavy populated European coastal areas: strong anthropogenic pressure but also area very important for recreation, tourism and resources The Mediterranean, as seen by satellite at night from Bosc et al., 2004 Low nutrient Low chlorophyll, highly stratified, P limitation Strong spatial trophic gradients with high intra- annual variations

3. What will be the marine Mediterranean ecosystem response to the changes of : Climatic drivers Temperature/ Acidification Circulation/ Stratification Light Extrem events Anthropogenic drivers Habitats/ Fishing Pollution/ Contaminants change in nutrient inputs and stoechiometric ratio MERMeX Impact on recreation, tourism, resources? SCIENTIFIC OBJECTIVES Bacteria/Virus Dissolved Organic matter NUTRIENTS Mammals Fish Zoo-organisms Phyto-organisms

4. Effect of change of stratification/destratification and surface hydrodynamics on the «nutrient-cline» evolution? Effect of change of convection on nutrients, organic matter transfer and remineralization between surface and deep layers? Effect of change of thermo-haline circulation on the biogenic elements budgets at the straits? MAIN TOPICS MERMeX INFLUENCE of EXTREME EVENTS? Impact of massive atmospheric inputs on oceanic productivity in oligotrophic regions (Links with CHARMEX) Large scale circulation (after Pinardi, 1997) INFLUENCE OF HYDRODYNAMICS? (Links with HYMEX) Massive inputs of aerosols (Saharan +Biomass burning in summer 2007 Rhone flood in 2002 Impact of massive river inputs of sediment, contaminants, nutrients, and organic matter on the spatial assemblage of benthic and pelagic ecosystems.

5. MAIN TOPICS MERMeX INFLUENCE OF TEMPERATURE and ACIDIFICATION? Effect on the main biological processes: Primary production, remineralization and calcification Effect on biodiversity, including change in the structure community, exotic species migration and on food web functioning? Possibility for acclimation and/or adaptation? From DYFAMED time-series data (Marty et Chiavérini, in rev.) Temp. increase in Deep waters : + 0.05 ° in 10 years Tropical toxic algae on French Riviera coast in summer 2008 Temporal trend for anthropogenic CO 2 at DYFAMED, Touratier & Goyet sub. Effect on the solubility pump? Consequences for anthropogenic CO 2 sequestration?

6. MAIN TOPICS MERMeX INFLUENCE OF LIGHT RADIATION (Links with CHARMEX) Effect of solar radiation variation (UVR/PAR) on solar radiation penetration in Mediterranean waters? Effects of solar penetration variation on ecosystems: primary production, Food web structure, organic volatile production, CO 2 fluxes Effect on primary production, heterotrophic mineralization and carbon sequestration efficiency What can we learn from changes of stoechiometric ratio of biogenic elements on those impacts? For example, is N 2 fixation a response to stratified and nutrient-depleted ecosystems, or a shift from siliceous to non siliceous organisms could be expected? INFLUENCE OF STOECHIOMETRIC RATIO Evolution of N/P in 3 rivers NWMed: impact of anthropogenic activity UV/Visible doses in Med >> oceanic areas located in the same degrees of latitude owing to its weak cloudy coverage, Watts.m-2, mean over 1 month- March 97

7. MAIN TOPICS MERMeX INFLUENCE OF CHEMICAL CONTAMINANTS (CC) Does oligotrophy favor CC bioaccumulation and bioamplification along the food webs? Consequence of changes in PP and carbonate dynamic for the CC fluxes? What is the real status of “new pollutants” in the Mediterranean Sea, including pharmaceutical products? Could they have any impact on the trophic food chain? Bioactive TEs also have a potential toxicity and may inhibit biological development INFLUENCE OF HABITAT AND RESOURCE Effects of environmental changes on species and communities spatial distribution. Impact on ecoregions spatial extent? Northern extension of southern species or assemblages? Biogeochemical fluxes among ecoregions: what is the role of each species in the biogeochemical fluxes, their contribution to production, biomass? Do system stability and resilience rely on a rather small number of species?

8. MAIN TOPICS MERMeX... strong interaction between experimental approaches and modeling: Can we build a group of accurate models able to simulate the evolution of the Mediterranean marine ecosystems according to different scenario? Numerical modeling in MERMEX: complex situations where all forcing coexist and interfere. “MERMEX models” : answer large spectra of questions from functional aspects of the Mediterranean ecosystem (e.g. its capacity to sequestrate carbon) to the influence of contaminants along the food web. “MERMEX models” should be able to represent the continuum going from the coast to the deep sea to deal with the fate of continental inputs under present and future conditions. MODELING Habitats/ Fishing Pollution/ Contaminants change in nutrient inputs and stoichiometric ratio Anthropogenic driversClimatic drivers Temperature/ Acidification Circulation/ Stratification Light Extrem events Bacteria/Virus Dissolved Organic matter NUTRIENTS Mammals Fish Zoo-organisms Phyto-organisms Impact on recreation, tourism, ressources?

9. Writing of a White book This work is in progress and will constitute a large publication: this review article will be submitted to Progress in Oceanography by the end of 2008 and publication might be expected for 2009-2010. MERMeX PROJECT LIFE http://mermex.com.univ-mrs.fr/ MERMeX Web site Communications Special Session Joint CIESM/ CNRS/ INSU Session (ASLO 2009, Nice) “Signals of Change in the Mediterranean and Black Seas: Multi-Lateral Initiatives” 34 submitted abstracts Letter of intend (LEFE): Objectives 2009: Implementation of MERMeX (cf talk tomorrow)